1. Field of the Invention:
This invention relates to vehicle seat back latch mechanisms, and more particularly to inertia-responsive vehicle seat back latch mechanisms.
2. Description of the Prior Art:
The prior art discloses the exploitation of inertia and gravity to provide latching mechanisms for vehicle seat backs. However, none of these prior art mechanisms employs a means for maintaining the seat back in its locked condition subsequent to a vehicle deceleration.
While all prior inertia-responsive seat back latch mechanisms will lock a vehicle seat back and prevent it from tilting forward during a sudden deceleration, such as is experienced during a frontal crash, these mechanisms become inoperative when deceleration ceases. Because all seat backs will exhibit some flexibility during a frontal crash, the locked seat back will flex forward during the first stage of the crash, thereby absorbing energy. During the intermediate stage of the crash, the seat back will then flex back through its original upright position and back to a new flexed position. At this stage of the crash, the vehicle has stopped decelerating or is merely slowly decelerating. Now the seat back, in its back, flexed position, flies forward again, but because the vehicle is no longer decelerating, the latching mechanism will not activate and therefore will not prevent the seat back from tilting forward. This phenomenon is known as seat back rebound, and results in serious passenger injuries notwithstanding the presence of conventional seat back latch mechanisms.
It is therefore a primary object of this invention to provide a new inertia-responsive seat back latch mechanism, and to provide a seat back latch mechanism which will prevent seat back rebound.
It is also an object of this invention to provide a new inertia-responsive seat back latch mechanism which will maintain the seat back in a locked condition subsequent to a vehicle deceleration.
An other object of this invention is to provide a new inertia-responsive seat back latch mechanism which will maintain the seat back in a locked condition subsequent to a vehicle deceleration greater than a predetermined value.
Yet another object of this invention is to provide a new inertia-responsive seat back latch mechanism which will cause the seat back to be in a locked condition during a vehicle deceleration greater than a first predetermined value and maintain the seat back in a locked condition subsequent to a vehicle deceleration greater than a second predetermined value, which value is greater than the first predetermined value.
These and other objects and features of this invention will become apparent to those skilled in the art by reference to the following description and drawings.